It is an exploration of the question 'where do extra-normal experiences come from?'
Smith tries to answer it and is told by the first psychologist he calls that nobody has done any research on that question, so he sets out to find it himself. He talks to every manner of explorer - shamans, trippers, sensory deprivation, near-death experience, advances in brain science such as in
To be nobody but yourself in a world which is doing its best, night and day, to make you everybody else means to fight the hardest battle which any human being can fight; and never stop fighting.
e. e. cummings
Call me flak-catcher.